test_that("a solution is found in the two-tensor case", {
  set.seed(123)
  I = 10
  J = 5
  K = 3
  L = 8
  M = 3
  A = array(rnorm(I*2), c(I, 2))
  B = array(rnorm(J*2), c(J, 2))
  C = array(rnorm(K*2), c(K, 2))
  D = array(rnorm(L*2), c(L, 2))
  E = array(rnorm(M*2), c(M, 2))

  df1 = reinflateTensor(A, B, C)
  df2 = reinflateTensor(A, D, E)
  datasets = list(df1, df2)
  modes = list(c(1,2,3), c(1,4,5))
  Z = setupCMTFdata(datasets, modes, normalize=FALSE)

  expect_no_error(cmtf_opt(Z, 1, max_iter=2))
})

test_that("a solution is found when running LBFGS", {
  set.seed(123)
  I = 10
  J = 5
  K = 3
  L = 8
  M = 3
  A = array(rnorm(I*2), c(I, 2))
  B = array(rnorm(J*2), c(J, 2))
  C = array(rnorm(K*2), c(K, 2))
  D = array(rnorm(L*2), c(L, 2))
  E = array(rnorm(M*2), c(M, 2))

  df1 = reinflateTensor(A, B, C)
  df2 = reinflateTensor(A, D, E)
  datasets = list(df1, df2)
  modes = list(c(1,2,3), c(1,4,5))
  Z = setupCMTFdata(datasets, modes, normalize=FALSE)

  expect_no_error(cmtf_opt(Z, 1, max_iter=2, method="L-BFGS"))
})

test_that("the objective is very high if an incorrect solution is found", {
  set.seed(123)
  I = 10
  J = 5
  K = 3
  L = 8
  M = 3
  A = array(rnorm(I*2), c(I, 2))
  B = array(rnorm(J*2), c(J, 2))
  C = array(rnorm(K*2), c(K, 2))
  D = array(rnorm(L*2), c(L, 2))
  E = array(rnorm(M*2), c(M, 2))

  df1 = reinflateTensor(A, B, C)
  df2 = reinflateTensor(A, D, E)
  datasets = list(df1, df2)
  modes = list(c(1,2,3), c(1,4,5))
  Z = setupCMTFdata(datasets, modes, normalize=FALSE)

  result = cmtf_opt(Z, 2, initialization="random", max_iter=2)
  expect_gt(result$f, 0)
})

test_that("allOutput=TRUE gives a list of expected length", {
  set.seed(123)
  I = 10
  J = 5
  K = 3
  L = 8
  M = 3
  A = array(rnorm(I*2), c(I, 2))
  B = array(rnorm(J*2), c(J, 2))
  C = array(rnorm(K*2), c(K, 2))
  D = array(rnorm(L*2), c(L, 2))
  E = array(rnorm(M*2), c(M, 2))

  df1 = reinflateTensor(A, B, C)
  df2 = reinflateTensor(A, D, E)
  datasets = list(df1, df2)
  modes = list(c(1,2,3), c(1,4,5))
  Z = setupCMTFdata(datasets, modes, normalize=FALSE)

  results = cmtf_opt(Z, 2, initialization="random", nstart=3, max_iter=2, allOutput=TRUE)
  expect_equal(length(results), 3)
})

test_that("the loss term per block has the correct length", {
  set.seed(123)
  I = 10
  J = 5
  K = 3
  L = 8
  M = 3
  A = array(rnorm(I*2), c(I, 2))
  B = array(rnorm(J*2), c(J, 2))
  C = array(rnorm(K*2), c(K, 2))
  D = array(rnorm(L*2), c(L, 2))
  E = array(rnorm(M*2), c(M, 2))

  df1 = reinflateTensor(A, B, C)
  df2 = reinflateTensor(A, D, E)
  datasets = list(df1, df2)
  modes = list(c(1,2,3), c(1,4,5))
  Z = setupCMTFdata(datasets, modes, normalize=FALSE)
  model = cmtf_opt(Z, 1, max_iter=2)
  expect_true(length(model$f_per_block)==2)
})

test_that("the sum of the the loss term per block is equal to the overall loss", {
  set.seed(123)
  I = 10
  J = 5
  K = 3
  L = 8
  M = 3
  A = array(rnorm(I*2), c(I, 2))
  B = array(rnorm(J*2), c(J, 2))
  C = array(rnorm(K*2), c(K, 2))
  D = array(rnorm(L*2), c(L, 2))
  E = array(rnorm(M*2), c(M, 2))

  df1 = reinflateTensor(A, B, C)
  df2 = reinflateTensor(A, D, E)
  datasets = list(df1, df2)
  modes = list(c(1,2,3), c(1,4,5))
  Z = setupCMTFdata(datasets, modes, normalize=FALSE)
  model = cmtf_opt(Z, 1, max_iter=2)
  expect_equal(sum(model$f_per_block), model$f)
})

test_that("running in parallel works", {
  skip_on_cran()

  set.seed(123)
  I = 10
  J = 5
  K = 3
  L = 8
  M = 3
  A = array(rnorm(I*2), c(I, 2))
  B = array(rnorm(J*2), c(J, 2))
  C = array(rnorm(K*2), c(K, 2))
  D = array(rnorm(L*2), c(L, 2))
  E = array(rnorm(M*2), c(M, 2))

  df1 = reinflateTensor(A, B, C)
  df2 = reinflateTensor(A, D, E)
  datasets = list(df1, df2)
  modes = list(c(1,2,3), c(1,4,5))
  Z = setupCMTFdata(datasets, modes, normalize=FALSE)

  expect_no_error(cmtf_opt(Z,2,initialization="random", nstart=2, max_iter=2, numCores=2))
})